/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.com
*
* This program is free software: you can redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License along with this program.
* If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.preprocessing.sampling;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.ProcessSetupError.Severity;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MDInteger;
import com.rapidminer.operator.ports.metadata.MetaDataInfo;
import com.rapidminer.operator.ports.metadata.SimpleMetaDataError;
import com.rapidminer.operator.ports.quickfix.ParameterSettingQuickFix;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeInt;
import com.rapidminer.parameter.UndefinedParameterError;
import com.rapidminer.tools.RandomGenerator;
import java.util.Collections;
import java.util.List;
/**
* Absolute sampling operator. This operator takes a random sample with the given size. For example,
* if the sample size is set to 50, the result will have exactly 50 examples randomly drawn from the
* complete data set. Please note that this operator does not sample during a data scan but jumps to
* the rows. It should therefore only be used in case of memory data management and not, for
* example, for database or file management.
*
* @author Ingo Mierswa
*/
public class AbsoluteSampling extends AbstractSamplingOperator {
/** The parameter name for "The number of examples which should be sampled" */
public static final String PARAMETER_SAMPLE_SIZE = "sample_size";
public AbsoluteSampling(OperatorDescription description) {
super(description);
}
@Override
protected MDInteger getSampledSize(ExampleSetMetaData emd) throws UndefinedParameterError {
int absoluteNumber = getParameterAsInt(PARAMETER_SAMPLE_SIZE);
if (emd.getNumberOfExamples().isAtLeast(absoluteNumber) == MetaDataInfo.NO) {
getExampleSetInputPort().addError(
new SimpleMetaDataError(Severity.ERROR, getExampleSetInputPort(), Collections
.singletonList(new ParameterSettingQuickFix(this, PARAMETER_SAMPLE_SIZE, emd
.getNumberOfExamples().getValue().toString())), "exampleset.need_more_examples",
absoluteNumber + ""));
}
return new MDInteger(absoluteNumber);
}
@Override
public ExampleSet apply(ExampleSet exampleSet) throws OperatorException {
return exampleSet;
}
@Override
public List<ParameterType> getParameterTypes() {
List<ParameterType> types = super.getParameterTypes();
ParameterType type = new ParameterTypeInt(PARAMETER_SAMPLE_SIZE, "The number of examples which should be sampled",
1, Integer.MAX_VALUE, 100);
type.setExpert(false);
types.add(type);
types.addAll(RandomGenerator.getRandomGeneratorParameters(this));
return types;
}
}